This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2002-250020, filed Aug. 29, 2002, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
This invention relates to a load port used to receive a cassette having at least one substrate to be processed such as a wafer accommodated therein, remove the substrate to be processed from the cassette and transfer the same to a preset processing apparatus.
2. Description of the Related Art
A load port of the present invention is used to handle not only semiconductor wafers but also different types of substrate to be processed such as liquid crystal display glass substrates and photomask glass substrates. Further, as a processing apparatus to which the substrate to be processed is transferred, various processing apparatuses such as a manufacturing apparatus, visual inspection apparatus, electrical characteristic test apparatus are provided. However, in order to clearly and concretely explain the prior art associated with the present invention, a wafer used in a semiconductor manufacturing process is used as the substrate to be processed and a process in a probe apparatus, that is, an electrical characteristic test process for semiconductor elements formed on the wafer is explained as the wafer processing process in the following description.
Recently, in order to enhance the manufacturing yield in a semiconductor manufacturing process, the diameter of wafers has increased and wafers with a diameter of 300 mm are used in addition to conventional wafers with a diameter of 200 mm. Plural types of cassette are provided to receive substrates such as wafers. As some of the types of the cassette, cassettes for wafers with a diameter of 200 mm and cassettes for wafers with a diameter of 300 mm are provided. Further, as cassettes with different capacities, a small cassette capable of accommodating 13 wafers and a large cassette capable of accommodating 25 wafers are provided. As the shape of the cassette, an open-type cassette in which the eject port used to remove a wafer from the cassette is open and an integral-type cassette in which the eject port is covered with an open/close door are provided.
In the conventional load port, two type of device including a dedicated device capable of accommodating an integral-type cassette and an adaptable device capable of receiving only an open-type cassette are provided. It is difficult for the open-type cassette adaptable device to receive an integral-type cassette. Further, in order to use an open-type cassette in the dedicated device for the integral-type cassette, it is necessary to use a conversion kit. Therefore, when plural types of cassette are selectively used by use of one load port, troublesome operations for the operator such as management of the conversion kit, replacement of the conversion kit are required.
In Jpn. Pat. Appln. KOKAI Publication No. 2000-77490, a load port which can treat various types of cassette is described, but it is necessary to replace the cassette fixing table in the load port, and adjustment by the operator is required even when a common fixing table is used.
The height of a wafer received in the cassette is detected by use of a sensor prior to the next step of removing the wafer from the cassette after the cassette is loaded in the load port. At this time, it is necessary to adjust the sensor position according to the wafer size, but since adjustment is performed manually, intervention by the operator is required.
The present invention has been made in view of the above-described conventional technique.
An object based on one aspect of the present invention is to permit plural types of cassette to be received therein without using a conversion kit.
An object based on another aspect of the present invention is to automatically identify a cassette and permit automatic adjustment of a wafer position detecting sensor to be made based on the result of identification.
An object based on still another aspect of the present invention is to receive plural types of cassette completely automatically.
An object based on another aspect of the present invention is to smoothly open or close the cover which covers the load port.
As described above, the object of the present invention is to provide a load port which attains at least one of the above-described objects.
According to one aspect of the present invention, a load port which can selectively receive plural types of cassette having substrates to be processed accommodated therein and which has the following constituents is provided.
That is, the load port includes a main body, an opening portion (which has a configuration that opens in the three surfaces comprising the front and right and left side surfaces) formed in one side surface of the main body, a placement table formed in the opening portion and used to place the cassette thereon, a first sensor mechanism (which identifies the type of cassette placed on the placement table) provided on the placement table, plural types of clamp mechanism (each type of clamp mechanism clamps the cassette of the identified type according to the result of identification by the first sensor) provided on the placement table, and an up-down-type cover mechanism (which is vertically moved to open/close the three surfaces of the opening portion) which covers the opening portion of the main body.
According to another aspect of the present invention, a load port which can selectively receive plural types of cassette having substrates to be processed accommodated therein and which has the following constituents is provided.
That is, the load port includes a main body, an opening portion formed in one side surface of the main body, a placement table provided in the opening portion and used to place a cassette thereon, a first sensor mechanism (which identifies the type of cassette placed on the placement table) provided on the placement table, and plural types of clamp mechanism (each type of clamp mechanism clamps the cassette of the identified type according to the result of identification by the first sensor) provided on the placement table.
According to still another aspect of the present invention, a load port which can selectively receive plural types of cassette having substrates to be processed accommodated therein and which has the following constituents is provided.
That is, the load port includes a main body, an opening portion (which has a configuration that opens in the three surfaces comprising the front and right and left side surfaces) formed in one side surface of the main body, a placement table formed in the opening portion and used to place a cassette thereon, a clamp mechanism which holds the cassette placed on the placement table, and an up-down-type cover mechanism (which is vertically moved to open/close the three surfaces of the opening portion) which covers the opening portion of the main body.
The load port based on the various aspects of the present invention can include any one of preferable configurations or any combination thereof as follows.
The up-down-type cover mechanism includes a weight counterbalance mechanism which makes the up-down movement of the cover easy.
The up-down-type cover mechanism includes a damper which stops the cover at a desired position in the up-down movement process.
The first sensor mechanism includes a sensor which detects a cassette for substrates to be processed having a diameter of 200 mm and a sensor which detects a cassette for substrates to be processed having a diameter of 300 mm.
The types of the cassette include at least an open-type in which the eject port, through which a substrate to be processed is removed from the cassette, is open and an integral-type in which the eject port is covered with an open/close-type door.
The placement table includes a first information pad which detects whether the cassette is a small cassette in which the number of substrates to be processed accommodated therein is small or a large cassette in which the number of substrates to be processed accommodated therein is large.
The placement table includes a second information pad which detects whether the cassette is an open-type cassette or an integral-type cassette.
The first sensor mechanism outputs cassette identification information and the clamp mechanism includes a first control mechanism which automatically holds the cassette of the identified type and releases the holding operation based on the cassette identification information.
The load port includes a second sensor mechanism which detects the height of the position of a wafer in the cassette.
The second sensor mechanism includes two arm portions having sensors which detect the height of the position of a wafer in the cassette and a second control mechanism which adjusts the distance between the arm portions. The second control mechanism adjusts the distance between the arm portions so as to cope with the type of cassette based on the cassette type identification information from the first sensor mechanism.
The placement table includes a kinematic pin which positions the cassette.
The placement table includes a third sensor which detects the presence/absence of a cassette.
The load port includes a display mechanism which displays the state of the apparatus and an output signal from at least one of the first, second and third sensor mechanisms.
The load port is used in at least one of a probe apparatus which tests the electrical characteristic of an integrated circuit formed on the semiconductor wafer, a semiconductor manufacturing apparatus which manufactures semiconductors or semiconductor devices, and a semiconductor wafer observation apparatus which measures defects in wafers and electrical characteristics and the like.
According to the embodiments of this invention, plural types of cassette can be selectively received without using a conversion kit. The cassette is automatically identified and the wafer position searching sensor can be automatically adjusted based on the result of identification. Further, plural types of cassette can be selectively and completely automatically received. The cover for the load port in the embodiments of the present invention makes it possible to attain smooth opening/closing and the area occupied by the cover can be reduced.